Walking lawn mower

Abstract

To prevent such a state that a traveling direction of a sulky type mower is bent toward a slope of a ridge in the sulky type mower including a first mowing blade and the second mowing blade.SOLUTION: A sulky type mower includes a first housing 21 for storing a first mowing blade, a front wheel 1 and rear wheel 2, a control lever 4 and a second housing 22 for storing a second mowing blade 12. The sulky type mower further includes a support member 46 attached to the second housing 22 so as to project forward from the second housing 22, and an auxiliary wheel 33 attached to the support member 46. The sulky type mower includes attitude change parts 45, 50 and 51 capable of changing an attitude of the support member 46 into a straight traveling attitude A21 in which the auxiliary wheel 33 rotates in the longitudinal direction and an inclined attitude A22 in which the auxiliary wheel 33 rotates along a virtual direction extending diagonally forward of the first housing 21 side with respect to the longitudinal direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a walking type lawn mower equipped with a first cutting blade and a second cutting blade.

Background Art

[0002] An example of a walking type lawn mower is disclosed in Patent Document 1. In Patent Document 1, a first housing that houses a first cutting blade and a second housing that houses a second cutting blade are provided, and the second housing is supported on the left portion of the first housing so as to be able to change its posture up and down around a longitudinal axis along the front-rear direction. A front wheel and a rear wheel that support the first housing and an auxiliary wheel that supports the second housing are provided, and a steering handle extends rearward from the first housing.

[0003] Thereby, an operator standing on the upper surface portion of the ridge can mow the grass on the upper surface portion and the slope surface portion of the ridge by running the first housing on the upper surface portion of the ridge and running the second housing on the slope surface portion (inclined surface portion) of the ridge while holding the steering handle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, the rear wheel is rotationally driven so that the walking type lawn mower moves forward, and the front wheel and the auxiliary wheel are not rotationally driven and rotate as the walking type lawn mower moves forward. When a lot of grass grows on the upper surface portion and the slope surface portion of the ridge, as the walking type lawn mower moves forward, the first housing and the second housing receive resistance from the grass on the ridge.

[0006] The first housing receives the driving force for forward movement from the rear wheels, while the second housing does not receive the driving force for forward movement from the rear wheels. Therefore, as the walking type lawn mower moves forward, if the second housing receives resistance from the grass on the ridge, the second housing may tend to drop downward toward the lower side of the ridge face. When the above-mentioned situation occurs, the traveling direction of the walking type lawn mower may be bent toward the ridge face side, and the operator needs to correct the traveling direction of the walking type lawn mower with the steering handle. Therefore, there is room for improvement in terms of the maneuverability of the walking type lawn mower.

[0007] An object of the present invention is to prevent a state in which the traveling direction of a walking type lawn mower is bent toward the ridge face side as the walking type lawn mower moves forward in a walking type lawn mower equipped with a first cutting blade and a second cutting blade.

Means for Solving the Problems

[0008] The walking type lawn mower of the present invention includes a first housing that houses a first cutting blade that is rotationally driven, a front wheel attached to the first housing so as to be positioned in front of the first housing, a rear wheel attached to the first housing so as to be positioned behind the first housing, a steering handle attached to the first housing so as to extend rearward from the first housing, a second housing that houses a second cutting blade that is rotationally driven and is supported on the right or left portion of the first housing so as to be able to change its posture vertically around a front-rear axis along the front-rear direction, a support member attached to the second housing so as to protrude forward from the second housing, an auxiliary wheel attached to the support member so as to be positioned in front of the second housing, and a posture changing unit that can change the posture of the support member between a straight-ahead posture in which the auxiliary wheel rotates along the front-rear direction and a tilted posture in which the auxiliary wheel rotates along a virtual direction extending obliquely forward on the first housing side with respect to the front-rear direction. and provided at the rear part of the support member is provided.

[0009] According to the present invention, when the walking type lawn mower advances and the second housing receives resistance from the grass on the ridge, if a situation occurs where the second housing tends to move downward toward the lower side of the ridge flank, the posture changing unit may set the support member to an inclined posture. When the support member is set to an inclined posture, as the walking type lawn mower advances, the auxiliary wheels rotate while contacting the ridge flank and try to climb obliquely upward along the ridge flank. Accordingly, a force is generated to lift the second housing upward above the ridge flank.

[0010] Thereby, even when the second housing receives resistance from the grass on the ridge, the situation where the second housing tends to move downward toward the lower side of the ridge flank can be suppressed by the force that tries to lift the second housing upward above the ridge flank, and a state where the advancing direction of the walking type lawn mower is bent toward the ridge flank side can be suppressed. Therefore, the walking type lawn mower can advance stably, the need for the operator to correct the advancing direction of the walking type lawn mower with the steering handle is reduced, and the maneuverability of the walking type lawn mower is improved.

[0011] According to the present invention, when the walking type lawn mower advances and the second housing does not receive resistance from the grass on the ridge, the posture changing unit may set the support member to a straight-ahead posture. Thereby, it is possible to avoid a state in which a force is generated to lift the second housing upward above the ridge flank although a situation where the second housing tends to move downward toward the lower side of the ridge flank does not occur.

[0012] In the present invention, it is preferable that the posture changing unit is attached to the second housing so as to be able to change the posture of the support member around a vertical axis along the vertical direction. and having a portion extending rearward from the vertical axis a support base, and the support base the portion extending rearward from the vertical axis in the above is preferably provided with a fixing portion that can be fixed to and released from the second housing. and provided on the rear side of the vertical axis

[0013] According to the present invention, by providing a support base portion and a fixing portion, the posture changing portion can be simply configured.

[0014] In the present invention, the steering handle has a right handle portion and a left handle portion. The right handle portion has, in plan view, a right first portion extending obliquely rearward to the right from the first housing, a right second portion extending from the rear portion of the right first portion obliquely rearward to the right and toward the left-right center side of the steering handle rather than in the extending direction of the right first portion, and a right grip portion extending rearward along the front-rear direction from the rear portion of the right second portion. The left handle portion has, in plan view, a left first portion extending obliquely rearward to the left from the first housing, a left second portion extending from the rear portion of the left first portion obliquely rearward to the left and toward the left-right center side of the steering handle rather than in the extending direction of the left first portion, and a left grip portion extending rearward along the front-rear direction from the rear portion of the left second portion, which is preferable.

[0015] As the steering handle of a walking type lawn mower, for example, as disclosed in Patent Document 1, the right handle portion and the left handle portion linearly extend obliquely rearward to the right and obliquely rearward to the left from the first housing in plan view, and in many cases, a right grip portion and a left grip portion are provided along the front-rear direction at the rear end portions of the right handle portion and the left handle portion. An operator standing behind the walking type lawn mower holds the right grip portion and the left grip portion. In this case, the lateral interval between the right grip portion and the left grip portion is substantially uniquely determined by the general physique of the operator and the like.

[0016] According to the present invention, as described above, in a state where the lateral interval between the right grip portion and the left grip portion is substantially uniquely determined, even if the right first portion and the left first portion extend obliquely rearward to the right (obliquely rearward to the left) from the first housing at a relatively large angle, the right second portion and the left second portion can be smoothly connected to the right grip portion and the left grip portion from the rear portions of the right first portion and the left first portion via the right second portion and the left second portion. In other words, compared with a configuration in which the right handle portion and the left handle portion extend linearly obliquely right rearward and obliquely left rearward from the first housing in plan view, the lateral interval between the front-rear intermediate portion of the right handle portion and the front-rear intermediate portion of the left handle portion can be set to be large.

[0017] As a result, when an operator standing behind the walk-behind mower puts his body between the right handle portion and the left handle portion and extends his hands forward to operate the posture changing portion, the lateral interval between the front-rear intermediate portion of the right handle portion and the front-rear intermediate portion of the left handle portion is large, making it easier to operate the posture changing portion.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

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Figure 11

Figure 12

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Figure 14

Figure 15

Figure 16

Figure 17

Embodiments for Carrying out the Invention

[0019] In FIGS. 1 to 17, a walking type lawn mower equipped with a first cutting blade 11 and a second cutting blade 12 is shown, where F indicates the forward direction, B indicates the rearward direction, U indicates the upward direction, D indicates the downward direction, R indicates the right direction, and L indicates the left direction.

[0020] (Overall Configuration of the Walking Type Lawn Mower) As shown in FIGS. 1 and 2, the walking type lawn mower has a first housing 21 that houses the first cutting blade 11 which is a cutting blade, a second housing 22 that houses the second cutting blade 12 which is a cutting blade, front wheels 1 and rear wheels 2 attached to the first housing 21, an engine 3, a steering handle 4, an auxiliary wheel 33 attached to the second housing 22, and the like.

[0021] (Configuration of the First Housing) As shown in FIGS. 2, 6, 7, 8, and 12, the first housing 21 has a top plate portion 23, a vertical surface portion 24 located on the right side of the first housing 21, a fixed vertical side member 25 which is the rear surface portion of the first housing 21, a cover 27, and the like.

[0022] The vertical surface portion 24 is bolt - connected to the right part of the top plate portion 23 and can be replaced with another vertical surface portion 24 by removing the bolts. The fixed vertical side member 25 is bolt - connected to the rear part of the top plate portion 23 and can be replaced with another fixed vertical side member 25 by removing the bolts. The cover 27 is composed of a flexible rubber plate and is attached to the right and left parts of the front part of the top plate portion 23.

[0023] As shown in FIG. 8, the vertical surface portion 24 has a front portion 24a and a rear portion 24b, and is configured to be bent at an intermediate portion of the vertical surface portion 24 such that the direction of the front portion 24a intersects with the direction of the rear portion 24b.

[0024] The front portion 24a of the vertical surface portion 24 becomes the lateral surface portion on the opposite side of the axis P3 (refer to (Configuration of the second housing) described later) in the first housing 21, and the rear portion 24b of the vertical surface portion 24 becomes the connection portion between the front portion 24a of the vertical surface portion 24 and the fixed vertical side member 25 which is the rear surface portion of the first housing 21. The rear portion 24b of the vertical surface portion 24 is formed so as to follow the rotation locus C1 (refer to (States of the first cutting blade and the second cutting blade) described later) of the outer peripheral portion of the first cutting blade 11 in a plan view.

[0025] (Configuration of the second housing) As shown in FIGS. 2, 6, 7, 8, 12, and 13, the second housing 22 has a top plate portion 28, a vertical surface portion 29, a vertical side member 30 which is an opening area changing portion, a cover 31, a guard member 32, an auxiliary wheel 33, and the like.

[0026] As shown in FIGS. 6, 8, 12, and 13, the vertical surface portion 29 has a lateral surface portion 29a located on the left portion of the second housing 22, a rear surface portion 29b located on the rear portion of the second housing 22, and an intermediate portion 29c. The vertical surface portion 29 is bolt - connected to the top plate portion 28 and can be replaced with another vertical surface portion 29 by removing the bolts.

[0027] The vertical side member 30 is attached to the rear surface portion 29b of the vertical surface portion 29 by bolts 34 which are an opening area changing portion and a position changing portion, and can be replaced with another vertical side member 30 by removing the bolts 34.

[0028] As shown in FIG. 2, the cover 31 is composed of a flexible rubber plate and is attached to the front portion of the top plate portion 28. The guard member 32 is composed of a round bar material and is attached to the front portion of the top plate portion 28.

[0029] As shown in FIGS. 2, 6, 7, and 8, the right part of the top plate portion 28 is attached to the left part of the top plate portion 23 so as to be vertically swingable around the axis P3, and the second housing 22 is supported by the left part of the first housing 21 so as to be vertically posture-changeable around the axis P3 which is the front-rear axis along the front-rear direction.

[0030] A wire (not shown) is connected across the angle adjustment lever 13 (refer to (Configuration of the steering handle) described later and FIG. 2) provided on the steering handle 4 and the second housing 22. By the angle adjustment lever 13, the second housing 22 can be set to a horizontal posture parallel to the first housing 21 and a downward posture directed obliquely downward from the first housing 21 (refer to FIGS. 6 and 7).

[0031] The angle adjustment lever 13 can set a plurality of downward postures with different angles. In this case, in each of the plurality of downward postures, the second housing 22 is stopped from swinging downward from the set angle and is allowed to swing upward from the set angle.

[0032] As shown in FIGS. 8 and 13, in the vertical surface portion 29, the horizontal surface portion 29a of the vertical surface portion 29 becomes the horizontal surface portion on the opposite side of the axis P3 in the second housing 22, the rear surface portion 29b of the vertical surface portion 29 becomes the rear surface portion of the second housing 22, and the intermediate portion 29c of the vertical surface portion 29 becomes the connection portion between the horizontal surface portion 29a and the rear surface portion 29b of the vertical surface portion 29.

[0033] The intermediate portion 29c of the vertical surface portion 29 is formed in an arc shape in plan view, and the intermediate portion 29c of the vertical surface portion 29 is formed along the rotation locus C2 (refer to (States of the first cutting blade and the second cutting blade) described later) of the outer peripheral portion of the second cutting blade 12 in plan view.

[0034] (Configuration regarding the support of the engine, steering handle, and rear wheels) As shown in FIGS. 2, 6, and 8, in the first housing 21, the frame 5 is connected to the rear portion of the top plate portion 23 along the left-right direction, and the engine 3 is supported by the frame 5.

[0035] Frame 6 is connected vertically along the right part of frame 5, and an angled frame 7 is connected vertically along the left part of frame 5. A handle base 8 is connected vertically to frame 7, and a steering handle 4 is attached to the handle base 8. The steering handle 4 is attached to the first housing 21 via the handle base 8 so as to extend rearward from the first housing 21.

[0036] As shown in FIGS. 1 and 2, a rear wheel support case 9 is provided, and a rear wheel 2 is supported at the lower part of the rear wheel support case 9. The upper part of the rear wheel support case 9 is connected to the handle base 8, the front part of the rear wheel support case 9 is connected to the upper part of the frame 6 via a bracket 10, and the lower part of the rear wheel support case 9 is connected to the right part of the frame 5 and the lower part of the frame 6. As described above, the rear wheel 2 that supports the first housing 21 is attached to the first housing 21 so as to be provided behind the first housing 21.

[0037] (Configuration of the steering handle) As shown in FIGS. 1 and 2, the steering handle 4 has a right handle part 81 and a left handle part 82 made of round pipes. The right handle part 81 has a right first part 81a, a right second part 81b, and a right handle part 81c, and the left handle part 82 has a left first part 82a, a left second part 82b, and a left handle part 82c.

[0038] The right first part 81a of the right handle part 81 extends obliquely right rearward from the handle base 8 (first housing 21) in plan view and obliquely upward rearward in side view. A hook part 81f is connected to the rear surface part of the right first part 81a.

[0039] The right second part 81b of the right handle part 81 extends obliquely right rearward from the rear part 81d of the right first part 81a in plan view, toward the approximate center side in the left - right direction of the steering handle 4 rather than the extending direction of the right first part 81a, and extends substantially horizontally rearward from the rear part 81d of the right first part 81a in side view.

[0040] The right handle part 81c of the right handle section 81 extends rearward along the front-rear direction from the rear part 81e of the right second part 81b in a plan view, and extends substantially horizontally rearward from the rear part 81e of the right second part 81b in a side view.

[0041] The left first part 82a of the left handle section 82 extends obliquely left-rearward from the handle base 8 (the first housing 21) in a plan view, and extends obliquely upward-rearward in a side view. The hook part 82f is connected to the rear surface part of the left first part 82a.

[0042] The left second part 82b of the left handle section 82 extends obliquely left-rearward from the rear part 82d of the left first part 82a, which is more toward the left-right center side of the steering handle 4 than the extending direction of the left first part 82a, in a plan view, and extends substantially horizontally rearward from the rear part 82d of the left first part 82a in a side view.

[0043] The left handle part 82c of the left handle section 82 extends rearward along the front-rear direction from the rear part 82e of the left second part 82b in a plan view, and extends substantially horizontally rearward from the rear part 82e of the left second part 82b in a side view.

[0044] An angle adjustment lever 13, a shift lever 55, a cutting clutch lever 72, and an accelerator lever 83 of the engine 3 are provided on the right handle section 81. A positioning lever 37, a traveling clutch lever 56, and a stop switch 84 of the engine 3 are provided on the left handle section 82.

[0045] (State of the steering handle) As shown in FIGS. 1 and 2, an operator standing behind the walking type lawn mower holds the right handle part 81c of the right handle section 81 and the left handle part 82c of the left handle section 82. In this case, the lateral interval W1 between the right handle part 81c of the right handle section 81 and the left handle part 82c of the left handle section 82 is substantially uniquely determined by the general build of the operator and the like.

[0046] According to the above description (configuration of the steering handle), the lateral interval W2 between the rear part 81d of the right first part 81a of the right handle part 81 and the rear part 82d of the left first part 82a of the left handle part 82 is large and close to the interval W1.

[0047] As described in the following (operations related to the attitude change of the support member and the auxiliary wheel), when setting the inclination attitude of the support member 46 and the support base 45 (auxiliary wheel 33), or when changing the attitude of the support member 46 up and down, an operator standing behind the walking type mower can fully insert his body between the right handle part 81 and the left handle part 82 of the steering handle 4.

[0048] Thereby, the operator can easily perform the operation of setting the inclination attitude of the support member 46 and the support base 45 (auxiliary wheel 33) and the operation of changing the attitude of the support member 46 up and down by extending his hand forward.

[0049] When mounting the walking type mower on the loading platform of a truck (not shown) for transportation, the walking type mower can be fixed to the loading platform of the truck by hanging a rope across the hook part of the loading platform of the truck and the hook parts 81f, 82f of the steering handle 4 (right handle part 81 and left handle part 82).

[0050] (Configuration related to the lateral support of the front wheels) As shown in FIGS. 4 and 5, in the first housing 21, a front wheel support member 14 is provided at the front part of the top plate part 23. The front wheel support member 14 is formed by bending a plate material, and the right part of the substrate part 14a of the front wheel support member 14 is attached to the top plate part 23 so as to be changeable in direction left and right around the axis P4 along the vertical direction.

[0051] A long hole 14b along the front-rear direction is opened in the left part of the substrate part 14a of the front wheel support member 14. A bolt 15 fixed upward to the top plate part 23 is inserted into the long hole 14b of the front wheel support member 14, and a fixing handle 16 having a female screw part is attached to the bolt 15.

[0052] On the substrate portion 14a of the front wheel support member 14, right and left support portions 14c are provided, and the front wheel support case 17 is supported so as to be swingable up and down around an axis P5 along the left - right direction. As shown in FIGS. 1 and 2, the front wheel support member 14 extends forward through between the covers 27 (refer to the above - mentioned (Configuration of the first housing)), and the front wheel 1 is supported at the front portion of the front wheel support case 17.

[0053] As shown in FIGS. 2 and 5, within the range of the long hole 14b of the front wheel support member 14, in a plan view, the posture of the front wheel support case 17 and the front wheel support member 14 can be changed left and right across a straight - ahead posture A11 in which the front wheel 1 rotates along the front - rear direction and an inclined posture A12 in which the front wheel 1 rotates along a virtual direction extending obliquely forward on the opposite side of the second housing 22 with respect to the front - rear direction.

[0054] The operator can fix the posture of the front wheel support member 14 by turning the fixed handle 16 to tighten the substrate portion 14a of the front wheel support member 14. The operator can change the posture of the front wheel support case 17 and the front wheel support member 14 left and right within the range of the long hole 14b of the front wheel support member 14 by turning the fixed handle 16 to loosen the tightening of the substrate portion 14a of the front wheel support member 14. Thus, the inclined posture of the front wheel support case 17 and the front wheel support member 14 (front wheel 1) can be set at an arbitrary position between the straight - ahead posture A11 and the inclined posture A12.

[0055] (Configuration regarding the vertical support of the front wheel) As shown in FIGS. 4 and 5, the positioning member 18 is connected to the front wheel support case 17 and extends rearward, and the positioning member 19 is connected to the rear portion of the positioning member 18. Three locking holes 19a are opened in the positioning member 19 so as to be arranged along the vertical direction.

[0056] The cylindrical member 20 is connected to the front wheel support member 14. A positioning pin 35 is provided on the cylindrical member 20 so as to be slidable along the front-rear direction, and a spring 36 for biasing the positioning pin 35 toward the protruding side is provided. A wire 38 is connected between the positioning lever 37 (see (Configuration of the steering handle) and FIG. 2 described above) and the positioning pin 35.

[0057] The operator holds the steering handle 4 and operates the positioning lever 37 to pull out the positioning pin 35 from the locking hole 19a of the positioning member 19, and operates the front part of the first housing 21 up and down with the rear wheel 2 as a fulcrum. Since the front wheel 1 is in contact with the ground due to the weight of the front wheel 1 and the front wheel support case 17, the posture of the front wheel support case 17 with respect to the first housing 21 is changed up and down.

[0058] When the front part of the first housing 21 reaches a desired height, the operator operates the positioning lever 37 and inserts the positioning pin 35 into one of the locking holes 19a of the positioning member 19, so that the posture of the front wheel support case 17 with respect to the first housing 21 can be set in three steps up and down, and the cutting height by the first cutting blade 11 can be set to a desired height. As described above, the front wheel 1 that supports the first housing 21 is attached to the first housing 21 so as to be provided in front of the first housing 21.

[0059] (Configuration related to the auxiliary wheel) As shown in FIGS. 2, 12, and 14, in the second housing 22, a support base 45, which is a posture changing portion formed by bending a plate material into a channel shape, is provided. The support base 45 is attached to the top plate portion 28 so as to be able to change its posture left and right around the axis P6, which is the vertical axis along the vertical direction.

[0060] A cylindrical support member 46 is provided, and the support member 46 is attached to the support base 45 so as to be able to change its attitude up and down around the axis P7 along the left - right direction. The support member 46 is attached to the second housing 22 via the support base 45 so as to protrude forward from the second housing 22, and the auxiliary wheel 33 is attached to the front end portion of the support member 46 so as to be located in front of the second housing 22.

[0061] A lock lever 47 is attached to the rear portion of the support member 46 so as to be able to swing up and down around the axis P8 along the left - right direction. By engaging the pin 47a of the lock lever 47 with one of the plurality of engaging portions 45a of the support base 45, the up - down attitude of the support member 46 can be fixed. A spring 48 is connected across the lock lever 47 and the support member 46, and the spring 48 biases the lock lever 47 toward the side where the pin 47a of the lock lever 47 engages with the engaging portion 45a of the support base 45.

[0062] As shown in FIGS. 2, 12, 15, and 16, a substrate member 49 is fixed to a portion immediately to the right of the rear portion of the support base 45 on the top plate portion 28, and a nut 49a is fixed to the upper portion of the substrate member 49. A flat - plate - shaped fixing member 50, which is an attitude - changing portion and a fixing portion, is connected to the right portion of the rear portion of the support base 45 and extends rightward from the support base 45 so as to be located above the substrate member 49.

[0063] A long hole 50a is opened in the fixing member 50, and the right end portion 50b of the fixing member 50 is bent downward. A fixing handle 51, which is an attitude - changing portion and a fixing portion, is provided, and a male screw portion is provided at the lower portion of the fixing handle 51.

[0064] (Operations related to the attitude change of the support member and the auxiliary wheel) As shown in FIGS. 2, 12, 15, and 16, within the range of the position where the rear portion of the support base 45 abuts against the left portion of the substrate member 49 and the position where the end portion 50b of the fixing member 50 abuts against the right portion of the substrate member 49, the support base 45 can change its attitude left and right around the axis P6.

[0065] As a result, as shown in FIG. 2, in a plan view, a straight-ahead posture A21 in which the auxiliary wheel 33 rotates along the front-rear direction (a position where the rear portion of the support base 45 hits the left portion of the substrate member 49), and an inclination along a virtual direction extending obliquely forward on the first housing 21 side with respect to the front-rear direction. The postures of the support member 46 and the support base 45 can be changed left and right over the posture A22 in which the auxiliary wheel 33 rotates (a position where the end portion 50b of the fixing member 50 hits the right portion of the substrate member 49).

[0066] As shown in FIGS. 2, 12, 15, and 16, the male screw portion of the fixed handle 51 is attached from the long hole 50a of the fixing member 50 to the nut 49a of the substrate member 49, and by turning the fixed handle 51 and tightening the fixing member 50, the support base 45 can be fixed to the second housing 22.

[0067] The operator can release the fixing of the support base 45 and change the postures of the support member 46 and the support base 45 left and right by turning the fixed handle 51 and loosening the tightening of the fixing member 50. By turning the fixed handle 51 and tightening the fixing member 50, the inclination postures of the support member 46 and the support base 45 (auxiliary wheel 33) can be set at an arbitrary position between the straight-ahead posture A21 and the inclination posture A22.

[0068] The operator can change the posture of the support member 46 up and down by gripping the rear portion of the support member 46 and the lock lever 47 and pulling out the pin 47a of the lock lever 47 from the engaging portion 45a of the support base 45. By engaging the pin 47a of the lock lever 47 with a desired engaging portion 45a of the support base 45, the cutting height by the second cutting blade 12 can be set to a desired height.

[0069] (Transmission structure to the front and rear wheels) As shown in FIGS. 1, 2, and 3, the transmission 53 is provided above the rear wheel support case 9. A transmission belt 54 is attached across the pulley 3b of the output shaft 3a of the engine 3 and the pulley 53b of the input shaft 53a of the transmission 53.

[0070] The transmission device 53 is provided with a traveling clutch (not shown) and is configured to be shiftable into three forward speeds and one reverse speed. A wire (not shown) is connected between the shift lever 55 (refer to the above-mentioned (configuration of the steering handle) and FIGS. 1 and 2) and the transmission device 53, and the transmission device 53 can be operated into three forward speeds and one reverse speed by the shift lever 55.

[0071] In the transmission device 53, the traveling clutch is biased to the disengaged state, and a wire (not shown) is connected between the traveling clutch lever 56 (refer to the above-mentioned (configuration of the steering handle) and FIG. 2) and the traveling clutch. When the operator holds and operates the traveling clutch lever 56 and pulls the wire toward the traveling clutch lever 56 side, the traveling clutch is operated into the transmission state. When the operator releases the hand from the traveling clutch lever 56, the traveling clutch is operated into the disengaged state.

[0072] Inside the rear wheel support case 9, a transmission chain 58 is attached between the sprocket 53d of the output shaft 53c of the transmission device 53 and the sprocket 57a of the axle 57 that supports the rear wheel 2. A transmission shaft 59 is provided at the upper and lower middle part of the rear wheel support case 9, and the sprocket 59a of the transmission shaft 59 meshes with the transmission chain 58.

[0073] As shown in FIGS. 1 to 5, a transmission shaft 63 is supported at the right front part of the first housing 21, and a transmission chain 64 is attached between the sprocket 59b of the transmission shaft 59 and the sprocket 63a of the transmission shaft 63.

[0074] The input shaft 65 of the front wheel support case 17 is arranged at the position of the axis P5, and the input shaft 65 and the transmission shaft 63 are connected via a universal joint 66. Inside the front wheel support case 17, a transmission chain 68 is attached between the sprocket 65a of the input shaft 65 and the sprocket 67a of the axle 67 that supports the front wheel 1.

[0075] With the above configuration, as shown in FIG. 3, the power of the engine 3 is transmitted to the transmission 53 via the transmission belt 54. The power transmitted by the transmission 53 is transmitted to the rear wheels 2 via the transmission chain 58, and is transmitted to the front wheels 1 via the transmission chain 58, the transmission shaft 59, the transmission chain 64, the transmission shaft 63, the input shaft 65, and the transmission chain 68. When the travel clutch of the transmission 53 is operated to the cut-off state, the front wheels 1 and the rear wheels 2 stop.

[0076] In this case, since the universal joint 66 is arranged so as to be located on the extension line of the axis P4, as described in the above (configuration regarding the support of the front wheels in the left-right direction), even if the postures of the front wheel support case 17 and the front wheel support member 14 are changed left and right around the axis P4, the power transmission from the transmission shaft 63 to the input shaft 65 can be performed without difficulty.

[0077] (Configuration of the first cutting blade and the second cutting blade) As shown in FIGS. 9, 10, and 11, the first cutting blade 11 and the second cutting blade 12 have an elongated rhombus-shaped base 60 in plan view, two first cutting blade portions 61, and two second cutting blade portions 62.

[0078] A large opening 60e is opened at the center of the base 60, and openings 60f are opened on both sides of the opening 60e. A first extension portion 60a extending from the opening 60e in one direction and a second extension portion 60b extending from the opening 60e in the other opposite direction are provided on the base 60.

[0079] In this case, the length of the base 60 of the second cutting blade 12 (the length extending between the end of the first extension portion 60a and the end of the second extension portion 60b) is configured to be longer than the length of the base 60 of the first cutting blade 11 (the length extending between the end of the first extension portion 60a and the end of the second extension portion 60b).

[0080] At the base 60, one edge of the first extension part 60a and the opposite edge of the second extension part 60b are formed on the inclined surface 60c, and the other edge of the first extension part 60a and the opposite edge of the second extension part 60b are formed on the inclined surface 60d. In FIG. 10, the inclined surface 60c of the base 60 faces obliquely downward, and the inclined surface 60d of the base 60 faces obliquely upward.

[0081] In the first cutting blade 11 and the second cutting blade 12, all four first cutting blade parts 61 and four second cutting blade parts 62 are configured in the same shape, and blade parts 61a, 61b, 62a, and 62b are formed on both the one and the other edges of the first cutting blade 11 and the second cutting blade 12.

[0082] In the first cutting blade 11, the first cutting blade part 61 is attached to both the upper and lower one - side and upper and lower the other - side portions of the first extension part 60a of the base 60 by a support pin 52 so as to be freely swingable around the axis P11 which is the first axis along the vertical direction. Thereby, the first cutting blade part 61 is provided on the first extension part 60a of the base 60 so as to extend outward from the first extension part 60a of the base 60.

[0083] In the second cutting blade 12, the second cutting blade part 62 is attached to both the upper and lower one - side and upper and lower the other - side portions of the second extension part 60b of the base 60 by a support pin 52 so as to be freely swingable around the axis P12 which is the second axis along the vertical direction. Thereby, the second cutting blade part 62 is provided on the second extension part 60b of the base 60 so as to extend outward from the second extension part 60b of the base 60.

[0084] (Configuration regarding the support of the first cutting blade and the second cutting blade) As shown in FIGS. 2, 6, 7, and 8, in the first housing 21, the cutting - blade case 26 is connected to the top - plate part 23. The drive shaft 41 is supported by the cutting - blade case 26 so as to be rotatable around the axis P1 which is the first vertical axis along the vertical direction, and a bracket 41a is connected to the lower part of the drive shaft 41 by a nut 39.

[0085] In the second housing 22, the cutting blade case 43 is connected to the top plate portion 28. The drive shaft 42 is supported by the cutting blade case 43 so as to be rotatable around the axis P2 which is the second vertical axis along the vertical direction, and the bracket 42a is connected to the lower portion of the drive shaft 42 by a nut 39.

[0086] As shown in FIGS. 7 and 8, a bottomed cylindrical cover 44 is provided. In the first housing 21, while the bottom of the cover 44 is sandwiched between the base portion 60 of the first cutting blade 11 and the bracket 41a of the drive shaft 41, the nut 39 is inserted into the opening 60e (see FIG. 11) of the base portion 60 of the first cutting blade 11, and the bolt 40 is connected across the opening 60f (see FIG. 11) of the base portion 60 of the first cutting blade 11 and the bracket 41a of the drive shaft 41, whereby the first cutting blade 11 and the cover 44 are attached to the lower portion of the drive shaft 41.

[0087] In the second housing 22, while the bottom of the cover 44 is sandwiched between the base portion 60 of the second cutting blade 12 and the bracket 42a of the drive shaft 42, the nut 39 is inserted into the opening 60e (see FIG. 11) of the base portion 60 of the second cutting blade 12, and the bolt 40 is connected across the opening 60f (see FIG. 11) of the base portion 60 of the second cutting blade 12 and the bracket 42a of the drive shaft 42, whereby the second cutting blade 12 and the cover 44 are attached to the lower portion of the drive shaft 42.

[0088] With the above configuration, in the first cutting blade 11 and the second cutting blade 12, the base portion 60 is attached to the lower portions of the drive shafts 41 and 42, and the base portion 60 has a first extension portion 60a extending from the lower portions of the drive shafts 41 and 42 toward one side, and a second extension portion 60b extending from the lower portions of the drive shafts 41 and 42 toward the other side opposite thereto.

[0089] In the first cutting blade 11 and the second cutting blade 12, the bolt 40 is removed, the base portion 60 is removed from the brackets 41a and 42a of the drive shafts 41 and 42, the first cutting blade 11 and the second cutting blade 12 are turned upside down, and then the base portion 60 is attached to the brackets 41a and 42a of the drive shafts 41 and 42 by the bolt 40 again, whereby the first cutting blade 11 and the second cutting blade 12 can be attached to the lower portions of the drive shafts 41 and 42.

[0090] As shown in the following (transmission structure to the first cutting blade and the second cutting blade) and FIGS. 8, 9, and 10, the first cutting blade 11 is rotationally driven in the rotational direction B1, and the second cutting blade 12 is rotationally driven in the rotational direction B2. The rotational direction B1 is counterclockwise in a plan view of the first housing 21, and the rotational direction B2 is clockwise in a plan view of the second housing 22.

[0091] With the above configuration, the first cutting blade 11 is rotatably supported around the axis P1, which is the first vertical axis along the vertical direction, and is housed in the first housing 21. The second cutting blade 12 is rotatably supported around the axis P2, which is the second vertical axis along the vertical direction, and is housed in the second housing 22.

[0092] (State of the first cutting blade and the second cutting blade) As shown in FIGS. 9 and 10, since the length of the base portion 60 of the second cutting blade 12 is longer than the length of the base portion 60 of the first cutting blade 11 (refer to the above item (Configuration of the first cutting blade and the second cutting blade)), the diameter D2 of the rotation locus C2 of the second cutting blade 12 is larger than the diameter D1 of the rotation locus C1 of the first cutting blade 11.

[0093] Below the connection portion (axis P3) between the first housing 21 and the second housing 22, the rotation locus C1 of the first cutting blade 11 and the rotation locus C2 of the second cutting blade 12 partially overlap in a plan view.

[0094] Since all four first cutting blade portions 61 and four second cutting blade portions 62 are configured in the same shape (refer to the above-mentioned (Configuration of the first cutting blade and the second cutting blade)), in the first cutting blade 11 and the second cutting blade 12, the length L11 extending between the axis P11 and the outer end portion of the first cutting blade portion 61 and the length L12 extending between the axis P12 and the outer end portion of the second cutting blade portion 62 are the same length.

[0095] In the first cutting blade 11, the length L21 extending between the axis P1 of the drive shaft 41 and the axis P11, and the length L22 extending between the axis P1 of the drive shaft 41 and the axis P12 are the same length, and L11 and L12 are set to be longer than the lengths L21 and L22.

[0096] In the second cutting blade 12, the length L31 extending between the axis P2 of the drive shaft 42 and the axis P11, and the length L32 extending between the axis P2 of the drive shaft 42 and the axis P12 are the same length, and L31 and L32 are set to be longer than the lengths L11 and L12.

[0097] As shown in FIGS. 8 to 11, when the first cutting blade 11 and the second cutting blade 12 are rotationally driven in the rotational directions B1 and B2, blade portions 61a, 61b, 62a, and 62b are formed at both the upper and lower edges in the rotational directions B1 and B2 in the first cutting blade portion 61 and the second cutting blade portion 62. Both the upper and lower edges in the rotational directions B1 and B2 of the first extending portion 60a and the second extending portion 60b of the base portion 60 are formed on the inclined surfaces 60c and 60d.

[0098] The upper edge in the rotational directions B1 and B2 of the first extending portion 60a of the base portion 60 and the upper edge in the rotational directions B1 and B2 of the second extending portion 60b of the base portion 60 are formed on the inclined surface 60c that is obliquely downward with respect to the rotational directions B1 and B2.

[0099] The lower edge in the rotational directions B1 and B2 of the first extending portion 60a of the base portion 60 and the lower edge in the rotational directions B1 and B2 of the second extending portion 60b of the base portion 60 are formed on the inclined surface 60d that is obliquely upward with respect to the rotational directions B1 and B2.

[0100] As described in the above (configuration regarding the support of the first and second cutting blades), when the first cutting blade 11 and the second cutting blade 12 are turned upside down and attached to the lower portions of the drive shafts 41 and 42, the upper edge and the lower edge in the rotational directions B1 and B2 of the first extending portion 60a of the base portion 60 are interchanged, and the upper edge and the lower edge in the rotational directions B1 and B2 of the second extending portion 60b of the base portion 60 are interchanged.

[0101] As a result, the upper edges of the first extension portion 60a and the second extension portion 60b of the base portion 60 in the rotational directions B1 and B2 become the obliquely downward inclined surfaces 60d, and the lower edges of the first extension portion 60a and the second extension portion 60b of the base portion 60 in the rotational directions B1 and B2 become the obliquely upward inclined surfaces 60c.

[0102] (Transmission Structure to the First Cutting Blade and the Second Cutting Blade) As shown in FIGS. 1, 2, 3, and 7, in the first housing 21, the transmission shaft 69 is supported by the cutting blade case 26, and a transmission belt 70 is attached across the pulley 3c of the output shaft 3a of the engine 3 and the pulley 69a of the transmission shaft 69. Inside the cutting blade case 26, the bevel gear 41b of the drive shaft 41 and the bevel gear 69b of the transmission shaft 69 are engaged with each other.

[0103] A cutting clutch 71 of the tension pulley type is provided for the transmission belt 70. A wire (not shown) is connected across the cutting clutch lever 72 (refer to the above-mentioned (Configuration of the Steering Handle) and FIGS. 1 and 2) and the cutting clutch 71, and the cutting clutch 71 can be operated to a transmission state and an interruption state by the cutting clutch lever 72.

[0104] In the second housing 22, the transmission shaft 73 is supported by the cutting blade case 43, and the transmission shaft 69 and the transmission shaft 73 are connected via two universal joints 74 and an extendable transmission shaft 75. Inside the cutting blade case 43, the bevel gear 42b of the drive shaft 42 and the bevel gear 73a of the transmission shaft 73 are engaged with each other.

[0105] As shown in FIGS. 1, 2, and 3, a metal cover 76 is attached to the first housing 21, and the cover 76 covers the output shaft 3a and pulleys 3b and 3c of the engine 3, the transmission belt 54, the input shaft 53a and pulley 53b of the transmission 53, the transmission shaft 59 (sprocket 59b), the transmission chain 64, the transmission shaft 63 (sprocket 63a), the transmission shaft 69 (pulley 69a), the transmission belt 70, the cutting clutch 71, etc.

[0106] As shown in FIGS. 2, 6, and 7, a cylindrical cover 77 that is stretchable and flexible is attached across the cutting blade case 26 and the cutting blade case 43, and a universal joint 74 and a transmission shaft 75 are accommodated inside the cover 77.

[0107] With the above configuration, as shown in FIG. 3, the power of the engine 3 is transmitted to the drive shaft 41 via the transmission belt 70 and the transmission shaft 69, and is transmitted to the drive shaft 42 via the transmission shaft 69, the universal joint 74, the transmission shaft 75, and the transmission shaft 73.

[0108] As shown in FIGS. 8, 9, and 10, the drive shaft 41 and the first cutting blade 11 are rotationally driven in the rotational direction B1, and the drive shaft 42 and the second cutting blade 12 are rotationally driven in the rotational direction B2. The rotational trajectories C1, C2 and the rotational directions B1, B2 are set so that the first cutting blade 11 and the second cutting blade 12 move rearward at the position of the axis P3. When the cutting clutch 71 is operated to the disengaged state, the first cutting blade 11 and the second cutting blade 12 stop.

[0109] In this case, as described in the above (Configuration of the second housing), even if the posture of the second housing 22 is changed vertically, the universal joint 74 bends and the transmission shaft 75 expands and contracts, so that the power transmission from the transmission shaft 69 to the transmission shaft 73 is performed without difficulty.

[0110] (Configuration regarding the opening for discharging the cut grass cut by the first cutting blade and the second cutting blade) As shown in FIGS. 6, 8, and 12, in the first housing 21, the left end portion of the fixed vertical side member 25 is located on the left and right center side (drive shaft 41 side) of the first housing 21 rather than the left end portion of the top plate portion 23.

[0111] As a result, an opening 78 is formed in a portion of the fixed vertical side member 25 of the first housing 21 adjacent to the second housing 22 so as to be located behind the axis P3 (the connection portion between the first housing 21 and the second housing 22), and grass clippings can be discharged rearward. The opening 78 is provided so as to be located on the left side, which is the side of the second housing 22, with respect to the rear wheels 2 in a rear view and a plan view (see FIG. 2).

[0112] In a plan view, the left rear portion of the top plate portion 23 of the first housing 21 and the fixed vertical side member 25 are located in front of the vertical side member 30 of the second housing 22. In a rear view, the left rear portion of the top plate portion 23 of the first housing 21, the fixed vertical side member 25, and the vertical side member 30 of the second housing 22 form the outer peripheral portion of the opening 78.

[0113] The vertical side portion 25a of the fixed vertical side member 25 becomes the right vertical side portion on the side of the rear wheels 2 at the right and left vertical side portions of the opening 78. In a rear view, the lower portion of the vertical side portion 25a of the fixed vertical side member 25 is separated laterally outward from the upper portion of the vertical side portion 25a of the fixed vertical side member 25 with respect to the left and right center of the opening 78 (so as to be located on the side of the rear wheels 2), and the vertical side portion 25a of the fixed vertical side member 25 is inclined in a rear view.

[0114] The extension portion 25b of the fixed vertical side member 25 extends obliquely rearward and toward the left and right center of the opening 78 from the vertical side portion 25a of the fixed vertical side member 25, and the extension portion 25b of the fixed vertical side member 25 becomes the extension portion provided on the right vertical side portion of the opening 78.

[0115] The vertical side portion 30a of the vertical side member 30 becomes the left vertical side portion on the opposite side of the rear wheels 2 at the right and left vertical side portions of the opening 78. In a rear view, the lower portion of the vertical side portion 30a of the vertical side member 30 is separated laterally outward from the upper portion of the vertical side portion 30a of the vertical side member 30 with respect to the left and right center of the opening 78 (so as to be located on the opposite side of the rear wheels 2), and the vertical side portion 30a of the vertical side member 30 is inclined in a rear view.

[0116] The extending portion 30b of the vertical side member 30 extends obliquely from the vertical side portion 30a of the vertical side member 30 toward the rear and the left - right center of the opening 78, and the extending portion 30b of the vertical side member 30 becomes an extending portion provided on the vertical side portion on the right side of the opening 78.

[0117] As described above (Configuration of the second housing) and as shown in FIG. 6, when the second housing 22 is set to a downward posture facing obliquely downward from the first housing 21, the vertical side portion 30a and the extending portion 30b of the vertical side member 30 approach an upright posture. When the second housing 22 is set to a horizontal posture parallel to the first housing 21, the vertical side portion 30a and the extending portion 30b of the vertical side member 30 are in the inclined posture as described above.

[0118] As shown in FIGS. 2 and 6, a bracket 79 is connected to the lower part of the frame 7 so as to face rearward. A pressing member 80 made of a flexible rubber plate is attached to the bracket 79 and extends obliquely rearward and downward, and the pressing member 80 is disposed behind the opening 78.

[0119] (Configuration regarding the change in the opening area of the opening for discharging the cut grass cut by the first cutting blade and the second cutting blade) As shown in FIGS. 6, 8, 12, and 13, a long hole 30c which is an opening - area changing portion and a position - changing portion is opened in the vertical side member 30 along the left - right direction. When a bolt 34 is inserted into the long hole 30c of the vertical side member 30 and tightened to the rear surface portion 29b of the vertical surface portion 29, the vertical side member 30 is fixed to the rear surface portion 29b of the vertical surface portion 29.

[0120] By loosening the bolt 34, the vertical side member 30 can be moved in the left - right direction with respect to the rear surface portion 29b of the vertical surface portion 29. When the vertical side member 30 is moved to the left and separated from the fixed vertical side member 25, the opening area of the opening 78 becomes larger. When the vertical side member 30 is moved to the right and brought closer to the fixed vertical side member 25, the opening area of the opening 78 becomes smaller.

[0121] (State of the ridge mowing operation) When performing the weeding operation on the ridge with a walking type lawn mower, as shown in Figs. 6, 7, and 17, the first housing 21 is moved on the upper surface E1 of the ridge by the front wheels 1 and the rear wheels 2, and the second housing 22 is moved on the side surface E2 of the ridge by the auxiliary wheels 33, thereby performing the weeding operation on the upper surface E1 and the side surface E2 of the ridge.

[0122] As described above (the configuration regarding the vertical support of the front wheels) and as shown in Fig. 4, the vertical posture of the front wheel support case 17 with respect to the first housing 21 is set to set the cutting height by the first cutting blade 11. As described above (the operation regarding the posture change of the support member and the auxiliary wheels) and as shown in Fig. 14, the cutting height by the second cutting blade 12 is set by changing the posture of the support member 46 vertically.

[0123] The front wheels 1 and the rear wheels 2 are rotationally driven, and the first housing 21 receives the driving force for forward movement from the front wheels 1 and the rear wheels 2. On the other hand, since the auxiliary wheels 33 are not rotationally driven, the second housing 22 does not receive the driving force for forward movement from the front wheels 1 and the rear wheels 2. As a result, as the walking type lawn mower moves forward, when the second housing 22 receives resistance from the grass on the side surface E2 of the ridge, the second housing 22 may tend to move downward toward the lower side of the side surface E2 of the ridge with the rear wheel 2 as a fulcrum (see arrow F1).

[0124] When the above situation occurs, as described above (the operation regarding the posture change of the support member and the auxiliary wheels) and as shown in Fig. 2, the left and right postures of the support member 46 and the support base 45 are set to an arbitrary inclined posture between the inclined posture A22 or the straight-ahead posture A21 and the inclined posture A22.

[0125] As the walking type lawn mower moves forward, the auxiliary wheels 33 rotate while contacting the side surface E2 of the ridge and tend to climb diagonally upward on the side surface E2 of the ridge (see arrow F2). Accordingly, a force (see arrow F3) that tends to lift the second housing 22 above the side surface E2 of the ridge is generated.

[0126] As a result, due to the length (moment arm) of the support member 46 extending forward from the first housing 21 and the moment caused by the aforementioned force (arrow F3), the situation where the second housing 22 tries to move downward with the rear wheel 2 as a fulcrum toward the lower side of the normal plane portion E2 of the ridge is suppressed.

[0127] If simply setting the left and right postures of the support member 46 and the support base 45 to the inclined posture A22 cannot suppress the situation where the second housing 22 tries to move downward with the rear wheel 2 as a fulcrum toward the lower side of the normal plane portion E2 of the ridge, as described above (the configuration regarding the left and right support of the front wheels) and as shown in FIG. 2, set the left and right postures of the front wheel support case 17 and the front wheel support member 14 to an arbitrary inclined posture between the inclined posture A12 or the straight-ahead posture A11 and the inclined posture A12.

[0128] As a result, a force (refer to arrow F4) is generated to move the first housing 21 to the opposite side of the normal plane portion E2 of the ridge by the front wheel 1, and the second housing 22 is pulled upward to the upper surface portion E1 of the ridge via the first housing 21, so the function of the aforementioned auxiliary wheel 33 is assisted.

[0129] (Cutting state by the first cutting blade and the second cutting blade) As described above (the state of the ridge mowing operation) and as shown in FIGS. 6, 7, and 8, when the first housing 21 travels on the upper surface portion E1 of the ridge, the first cutting blade 11 is rotationally driven in the rotation direction B1, so that grass is cut by the first cutting blade 11 near the front portion of the first housing 21. The cut grass moves rearward along the axis P3 as the first cutting blade 11 rotates and mainly exits rearward from the opening 78.

[0130] There may be a case where the cut grass does not exit rearward from the opening 78 and moves along the rear portion 24b and the front portion 24a of the vertical surface portion 24 from the fixed vertical side member 25 together with the first cutting blade 11. In this case, as described above (the configuration of the first housing) and as shown in FIG. 8, since the rear portion 24b of the vertical surface portion 24 is formed to follow the rotation locus C1 of the outer peripheral portion of the first cutting blade 11 in plan view, the cut grass rarely stays near the rear portion 24b of the vertical surface portion 24.

[0131] As described above (the state of the weeding operation on the ridge) and as shown in FIGS. 6, 7, and 8, when the second housing 22 travels on the ridge side surface E2, the second cutting blade 12 is rotationally driven in the rotational direction B2. As a result, near the front portion of the second housing 22, the grass is cut by the second cutting blade 12, and the cut grass moves rearward in the position of the axis P3 as the second cutting blade 12 rotates, and mainly exits rearward from the opening 78. There is little cut grass that exits rearward from between the rear surface portion 29b of the second housing 22 (vertical surface portion 29) and the ridge side surface E2, or from between the vertical side member 30 and the ridge side surface E2.

[0132] There are cases where the cut grass does not exit rearward from the opening 78, but moves along the intermediate portion 29c and the horizontal surface portion 29a of the vertical surface portion 29 together with the second cutting blade 12 from the rear surface portion 29b of the vertical surface portion 29. In this case, as described above (the configuration of the second housing) and as shown in FIG. 8, since the intermediate portion 29c of the vertical surface portion 29 is formed in an arc shape so as to follow the rotation locus C2 of the outer peripheral portion of the second cutting blade 12 in plan view, the cut grass rarely stays near the intermediate portion 29c of the vertical surface portion 29.

[0133] When the first cutting blade 11 and the second cutting blade 12 are rotationally driven, it is assumed that the upper edges of the first extension portion 60a and the second extension portion 60b of the base portion 60 bounce off small stones and the like on the upper surface portion E1 and the side surface portion E2 of the ridge.

[0134] As shown in FIGS. 8 and 11, in the first cutting blade 11 and the second cutting blade 12, since the upper edges of the first extension portion 60a and the second extension portion 60b of the base portion 60 are formed on the inclined surface 60c that is obliquely downward with respect to the rotational directions B1 and B2, the small stones and the like are not bounced off in the direction along the rotational directions B1 and B2 of the base portion 60, but are bounced off obliquely downward with respect to the rotational directions B1 and B2 of the base portion 60 and hit the upper surface portion E1 and the side surface portion E2 of the ridge.

[0135] As a result, the possibility that small stones and the like jump out of the first housing 21 and the second housing 22 to the outside is small. Even if small stones and the like jump out of the first housing 21 and the second housing 22 to the outside, the momentum of the small stones and the like jumping out is greatly suppressed.

[0136] As described in the foregoing (configuration regarding the support of the first cutting blade and the second cutting blade), even if the first cutting blade 11 and the second cutting blade 12 are turned upside down and attached to the lower parts of the drive shafts 41 and 42, the upper edges and the lower edges in the rotational directions B1 and B2 at the first extension part 60a of the base part 60 are interchanged, and the upper edges and the lower edges in the rotational directions B1 and B2 at the second extension part 60b of the base part 60 are interchanged.

[0137] As a result, the upper edges in the rotational directions B1 and B2 at the first extension part 60a and the second extension part 60b of the base part 60 become the downwardly inclined inclined surfaces 60d, so the same situation as described above can be obtained.

[0138] (Discharge state of the cut grass from the opening by the first cutting blade and the second cutting blade) As described in the foregoing (cutting state by the first cutting blade and the second cutting blade) and shown in FIGS. 2 and 17, when the cut grass comes out from the opening 78 rearward, the cut grass is formed into a single continuous streak-shaped (mountain-shaped) mass. The streak-shaped (mountain-shaped) mass of the cut grass is formed near the connection part between the upper surface part E1 and the side surface part E2 of the ridge, or near the top of the side surface part E2 of the ridge (see state G1).

[0139] As described in the foregoing (configuration regarding the opening for discharging the cut grass cut by the first cutting blade and the second cutting blade) and shown in FIGS. 2 and 6, due to the fact that the vertical side part 25a of the fixed vertical side member 25 is arranged inclined in a rear view, and the vertical side part 30a of the vertical side member 30 is arranged inclined in a rear view, the streak-shaped (mountain-shaped) mass of the cut grass is likely to be formed in a trapezoidal cross-section.

[0140] Due to the fact that the extension part 25b of the fixed vertical side member 25 extends obliquely rearward and toward the left and right center of the opening 78 from the vertical side part 25a of the fixed vertical side member 25, and the extension part 30b of the vertical side member 30 extends obliquely rearward and toward the left and right center of the opening 78 from the vertical side part 30a of the vertical side member 30, the lateral parts of the streak-shaped (mountain-shaped) mass of the cut grass are pressed and fixed by the extension part 25b of the fixed vertical side member 25 and the extension part 30b of the vertical side member 30.

[0141] Since the pressing member 80 is disposed behind the opening 78 and extends obliquely rearward and downward, the upper portion of the strip-shaped (mountain-shaped) mass of mowed grass is pressed firmly by the pressing member 80.

[0142] The opening area of the opening 78 may be increased or decreased by changing the position of the vertical side member 30 left and right according to the amount of grass in the ridge and the state of the grass (e.g., wet or dry after rain). Since the opening 78 is located on the side of the second housing 22 with respect to the rear wheel 2, the strip-shaped (mountain-shaped) mass of mowed grass coming out of the opening 78 is not crushed by the rear wheel 2.

[0143] As a result, the strip-shaped (mountain-shaped) mass of mowed grass is difficult to slide down the ridge face portion E2. Even if the strip-shaped (mountain-shaped) mass of mowed grass slides down the ridge face portion E2, the strip-shaped (mountain-shaped) mass of mowed grass is likely to stop in the middle portion of the ridge face portion E2 and rarely slides down to the field.

[0144] (First alternative embodiment of the invention) The support member 46 may be extended forward from the configuration shown in FIGS. 2 and 17 so that the auxiliary wheel 33 is located in front of the front wheel 1.

[0145] According to this configuration, the length (moment arm) of the support member 46 extending forward from the first housing 21 (see the above (state of the ridge grass cutting operation)) becomes longer, so the moment generated by this length (moment arm) and the above-described force (arrow F3) becomes larger.

[0146] (Second alternative embodiment of the invention) A plurality of auxiliary wheels 33 may be supported at the front portion of the support member 46 so as to be spaced apart in the left-right direction.

[0147] According to this configuration, as described in the above (state of the weeding work on the ridge), when the left and right postures of the support member 46 and the support base 45 are set to an arbitrary inclined posture between the inclined posture A22 or the straight-ahead posture A21 and the inclined posture A22, it becomes difficult for the auxiliary wheel 33 to skid laterally with respect to the ridge normal surface E2. Therefore, the certainty of the state where the auxiliary wheel 33 attempts to climb obliquely upward along the ridge normal surface E2 is improved.

[0148] (Third Alternative Embodiment of the Invention) In the guard member 32 at the front part of the second housing 22, the entire guard member 32 may be configured to be linear in plan view, and the entire guard member 32 may be arranged obliquely in plan view such that the portion of the guard member 32 on the first housing 21 side is located more forward than the portion of the guard member 32 on the opposite side of the first housing 21.

[0149] According to this configuration, when the second housing 22 advances along the ridge normal surface E2 during the weeding work on the ridge, the guard member 32 hits the grass on the ridge normal surface E2, causing a state where the guard member 32 attempts to climb obliquely upward along the ridge normal surface E2. As a result, the function of the auxiliary wheel 33 that generates a force to lift the second housing 22 above the ridge normal surface E2 (see arrow F3 in FIG. 17) can be assisted by the guard member 32.

[0150] (Fourth Alternative Embodiment of the Invention) The second housing 22 may be provided on the right part of the first housing 21.

Industrial Applicability

[0151] The present invention can be applied to a walking type lawn mower equipped with a first cutting blade and a second cutting blade.

Explanation of Reference Numerals

[0152] 1 Front wheel 2 Rear wheel 4 Steering handle 11 First cutting blade 12 Second cutting blade 21 First housing 22 Second housing 33 Auxiliary wheel 45 Support base (posture changing part) 46 Support member 50 Fixing member (fixing part) (posture changing part) 51 Fixing handle (fixing part) (posture changing part) 81 Right handle part 81a Right first part 81b Right second part 81c Right handle part 81d Rear part 81e Rear part 82 Left handle part 82a Left first part 82b Left second part 82c Left handle part 82d Rear part 82e Rear part A21 Straight - ahead posture A22 Tilted posture P3 Axis (front - rear axis) P6 Axis (vertical axis)

Claims

1. A first housing that houses a first cutting blade driven in rotation, A front wheel attached to the first housing so as to be positioned in front of the first housing, A rear wheel attached to the first housing so as to be positioned behind the first housing, A steering handle attached to the first housing so as to extend rearward from the first housing, A second housing that houses a second cutting blade driven in rotation and is supported on the right or left part of the first housing so as to be able to change its posture vertically around a longitudinal axis along the front-rear direction, A support member attached to the second housing so as to protrude forward from the second housing, An auxiliary wheel attached to the support member so as to be positioned in front of the second housing, A walking-type lawn mower comprising a posture-changing unit provided at the rear part of the support member, which can change the posture of the support member between a straight-ahead posture in which the auxiliary wheel rotates along the front-rear direction and a tilted posture in which the auxiliary wheel rotates along a virtual direction extending obliquely forward on the first-housing side with respect to the front-rear direction.

2. The posture-changing unit according to claim 1, wherein the posture-changing unit includes a support base that is attached to the second housing so as to be able to change its posture around a vertical axis along the vertical direction and has a portion extending rearward from the vertical axis, and a fixing unit that is provided on the rear side of the vertical axis and can fix and release the portion of the support base extending rearward from the vertical axis to the second housing.

3. The steering handle has a right handle part and a left handle part, The right handle part has, in plan view, a right first part extending obliquely right-rearward from the first housing, a right second part extending from the rear part of the right first part obliquely right-rearward toward the left-right center side of the steering handle rather than in the extension direction of the right first part, and a right grip part extending rearward along the front-rear direction from the rear part of the right second part. The left handle portion has, in plan view, a left first portion extending obliquely rearward to the left from the first housing, a left second portion extending obliquely rearward to the left toward the left-right center side of the steering handle rather than in the extending direction of the left first portion and extending from the rear portion of the left first portion, and a left grip portion extending rearward along the front-rear direction from the rear portion of the left second portion. The walking type lawn mower according to claim 1 or 2.

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